1. Field of the Invention
The present invention relates generally to a device for sharpening snow ski edges and more specifically to a motorized device for sharpening both the bottom and side edges of a snow ski or snowboard.
2. Description of the Prior Art
Down hill snow skis, including their cousin the snowboard, are made from a wide variety of materials including wood, fiberglass, plastic, resins and the like. Today""s ski bases are usually made from a hard resin plastic such as p-tex. All these skis have metal edges which run the length of both lower edges of the ski that are designed to aid in griping the snow and aid in turning. In order for the ski edge""s top performance characteristics to be maintained, both the side and bottom of the metal edge must be sharpened. Beveling of the metal edges is also done while sharpening. By beveling the edges, changes in the drag and turning characteristics can be greatly affected. The base bevel on modem skis can run from about zero to two degrees while the bevel on the side edge can run from about zero to five degrees.
Ski shops have typically been considered the best place to take skis for sharpening the ski edges. These shops can afford large motorized sharpening machines that hold the skis firmly in place and quickly and accurately sharpen the whole ski. But the time and cost of taking ones skis to a ski shop keeps most people from doing such sharpening as often as it should be done for optimum performance.
Accordingly, a wide variety of devices have been developed for sharpening ski edges away from the ski shop. They basically fall into two categories, manual sharpeners and motorized sharpeners.
Manual sharpeners tend to be a file with a file holder to maintain file alignment. There are serious problems however with the manual devices of the art. Specifically, these units are hard to keep aligned, removal of metal is uneven and because of the size of the file teeth, the file needs in general, to straddle both sides of the skis leading to problems with the p-tex base and interfering with even filing of the bottom edge. Because these manual sharpeners are extremely hard to use, people tend to discontinue their use rather rapidly. Another problem with manual sharpeners is the inability to adjust the angle on the file leaving the user with right angles (a zero degree bevel) as the only choice or at the very least the single choice of angles.
The majority of motorized sharpeners are the large floor or bench type models designed primarily for ski shop use. While there is at least one small hand held unit disclosed in the art, it suffers from difficulties in keeping the sanding disc at a proper angle since the motor, motor shaft and sanding disc are held parallel to the ski edge during use. The weight of the motor that is not supported in this configuration makes balance of the system impossible (French Patent 2,516,004). A further problem with this design is the tendency for the sanding disc to xe2x80x9crun-awayxe2x80x9d from the user if not held tightly.
Another problem with previous motorized, hand held ski sharpeners is the lack of teaching of how one would sharpen the side edges of the skis since only bottom edge sharpening are taught.
Accordingly, it is an object of the present invention to provide a novel hand held motorized ski sharpening device that overcomes the problems discussed above.
It is also an object of the invention to provide a ski edge sharpening device that is capable of sharpening skis at a desired bevel angle.
It is yet another object to provide a ski sharpening device that is capable of sharpening both the side and bottom edges of a ski.
It is a further object to provide a sharpening device for skis that is balanced to use, does not require frequent changes of abrasives, and does not encourage the abrasive to xe2x80x9crun-awayxe2x80x9d during use.
The present invention relates to hand held motorized devices designed to grind and sharpen the side and bottom edges of snow skis, including snowboards, at a desired bevel angle.
The device of the present invention uses a solid columnar grinding stone having a flat bottom portion to grind the bottom ski edge and a circumferential edge of the grinding stone to grind the side edge of the ski as the grinding wheel is moved along the length of the ski. The flat bottom portion can be angled as desired to give the desired bevel to the bottom edge. This grinding stone is driven by a hand held high-speed motor comprising a counter clockwise rotary driven shaft and wherein the grinding stone is spring-loaded for mounting in the drive shaft collet.
The motor is mounted to an edge guide holding the grinding stone against either the bottom edge or side edge as desired and consists of a base to lay flat on the ski, a runner portion to guide the base along the ski edge and a grinding stone aperture for allowing room for the grinding stone to be positioned against the bottom or side ski edge.
In one embodiment, the motor is mounted at an angle such that the desired bevel angle is shaped into the ski bottom edge while using a flat bottom grinding stone.
The edge guide is moved along the length of the ski with the grinding stone either against the bottom or side edge of the ski until the desired beveling and sharpening is obtained.